Add a mode flag to the tracing framework.

base/debug/trace_event_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 
 #ifndef BASE_DEBUG_TRACE_EVENT_IMPL_H_
 #define BASE_DEBUG_TRACE_EVENT_IMPL_H_
 
 #include "build/build_config.h"
 
@@ skipping 139 matching lines @@
 
   // When all fragments have been added, call Finish to complete the JSON
   // formatted output.
   void Finish();
 
  private:
   OutputCallback output_callback_;
   bool append_comma_;
 };
 
+// TraceMode determines how the trace buffer stores data.
+enum BASE_EXPORT TraceMode {
+  UNTIL_FULL = 0
+};
 
 class BASE_EXPORT TraceLog {
  public:
   // Notification is a mask of one or more of the following events.
   enum Notification {
     // The trace buffer does not flush dynamically, so when it fills up,
     // subsequent trace events will be dropped. This callback is generated when
     // the trace buffer is full. The callback must be thread safe.
     TRACE_BUFFER_FULL = 1 << 0,
     // A subscribed trace-event occurred.
     EVENT_WATCH_NOTIFICATION = 1 << 1
   };
 
   static TraceLog* GetInstance();
 
   // Get set of known categories. This can change as new code paths are reached.
   // The known categories are inserted into |categories|.
   void GetKnownCategories(std::vector<std::string>* categories);
 
   // Enable tracing for provided list of categories. If tracing is already
   // enabled, this method does nothing -- changing categories during trace is
   // not supported.
   // If both included_categories and excluded_categories are empty,
   //   all categories are traced.
   // Else if included_categories is non-empty, only those are traced.
   // Else if excluded_categories is non-empty, everything but those are traced.
   // Wildcards * and ? are supported (see MatchPattern in string_util.h).
   void SetEnabled(const std::vector<std::string>& included_categories,
-                  const std::vector<std::string>& excluded_categories);
+                  const std::vector<std::string>& excluded_categories,
+                  TraceMode mode);
 
   // |categories| is a comma-delimited list of category wildcards.
   // A category can have an optional '-' prefix to make it an excluded category.
   // All the same rules apply above, so for example, having both included and
   // excluded categories in the same list would not be supported.
   //
   // Example: SetEnabled("test_MyTest*");
   // Example: SetEnabled("test_MyTest*,test_OtherStuff");
   // Example: SetEnabled("-excluded_category1,-excluded_category2");
-  void SetEnabled(const std::string& categories);
+  void SetEnabled(const std::string& categories, TraceMode mode);
 
   // Retieves the categories set via a prior call to SetEnabled(). Only
   // meaningful if |IsEnabled()| is true.
   void GetEnabledTraceCategories(std::vector<std::string>* included_out,
                                  std::vector<std::string>* excluded_out);
 
+  TraceMode GetTraceMode() { return trace_mode_; }
+
   // Disable tracing for all categories.
   void SetDisabled();
   // Helper method to enable/disable tracing for all categories.
-  void SetEnabled(bool enabled);
+  void SetEnabled(bool enabled, TraceMode mode);
   bool IsEnabled() { return !!enable_count_; }
 
 #if defined(OS_ANDROID)
   void StartATrace();
   void StopATrace();
 #endif
 
   // Enabled state listeners give a callback when tracing is enabled or
   // disabled. This can be used to tie into other library's tracing systems
   // on-demand.
@@ skipping 174 matching lines @@
   unsigned long long process_id_hash_;
 
   int process_id_;
 
   TimeDelta time_offset_;
 
   // Allow tests to wake up when certain events occur.
   const unsigned char* watch_category_;
   std::string watch_event_name_;
 
+  TraceMode trace_mode_;
+
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_TRACE_EVENT_IMPL_H_